Acoustic technology is appropriated for quality assessment of a very large range of tree’s size and quality such as for trees belonging to the cultural heritage, for forest trees, for trees in plantations, for urban trees, for seedlings and even for forest seeds. Acoustic non-destructive methodology allows to study the characteristics of the standing trees and to detect some of the particularities of their living structure such as the pith, the juvenile wood, the reaction wood, the ring shake, the slope of grain, the cavities and the decay. The major effects of the sylvicultural treatments of forest trees in plantations such as thinning, pruning, etc., can be detected with acoustic technology.